Patch "powerpc/perf: Fix PMU constraint check for EBB events" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    powerpc/perf: Fix PMU constraint check for EBB events

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-perf-fix-pmu-constraint-check-for-ebb-events.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 30b90ef693124861b53e3a941aa5b50cb2d933fc
Author: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
Date:   Tue Apr 6 12:16:01 2021 -0400

    powerpc/perf: Fix PMU constraint check for EBB events
    
    [ Upstream commit 10f8f96179ecc7f69c927f6d231f6d02736cea83 ]
    
    The power PMU group constraints includes check for EBB events to make
    sure all events in a group must agree on EBB. This will prevent
    scheduling EBB and non-EBB events together. But in the existing check,
    settings for constraint mask and value is interchanged. Patch fixes the
    same.
    
    Before the patch, PMU selftest "cpu_event_pinned_vs_ebb_test" fails with
    below in dmesg logs. This happens because EBB event gets enabled along
    with a non-EBB cpu event.
    
      [35600.453346] cpu_event_pinne[41326]: illegal instruction (4)
      at 10004a18 nip 10004a18 lr 100049f8 code 1 in
      cpu_event_pinned_vs_ebb_test[10000000+10000]
    
    Test results after the patch:
    
      $ ./pmu/ebb/cpu_event_pinned_vs_ebb_test
      test: cpu_event_pinned_vs_ebb
      tags: git_version:v5.12-rc5-93-gf28c3125acd3-dirty
      Binding to cpu 8
      EBB Handler is at 0x100050c8
      read error on event 0x7fffe6bd4040!
      PM_RUN_INST_CMPL: result 9872 running/enabled 37930432
      success: cpu_event_pinned_vs_ebb
    
    This bug was hidden by other logic until commit 1908dc911792 (perf:
    Tweak perf_event_attr::exclusive semantics).
    
    Fixes: 4df489991182 ("powerpc/perf: Add power8 EBB support")
    Reported-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
    Signed-off-by: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
    [mpe: Mention commit 1908dc911792]
    Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/1617725761-1464-1-git-send-email-atrajeev@xxxxxxxxxxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c
index e1a21d34c6e4..5e8eedda45d3 100644
--- a/arch/powerpc/perf/isa207-common.c
+++ b/arch/powerpc/perf/isa207-common.c
@@ -400,8 +400,8 @@ ebb_bhrb:
 	 * EBB events are pinned & exclusive, so this should never actually
 	 * hit, but we leave it as a fallback in case.
 	 */
-	mask  |= CNST_EBB_VAL(ebb);
-	value |= CNST_EBB_MASK;
+	mask  |= CNST_EBB_MASK;
+	value |= CNST_EBB_VAL(ebb);
 
 	*maskp = mask;
 	*valp = value;